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  2. Regular expression - Wikipedia

    en.wikipedia.org/wiki/Regular_expression

    Algebraic laws for regular expressions can be obtained using a method by Gischer which is best explained along an example: In order to check whether (X+Y) ∗ and (X ∗ Y ∗) ∗ denote the same regular language, for all regular expressions X, Y, it is necessary and sufficient to check whether the particular regular expressions (a+b) ∗ and ...

  3. Wildcard character - Wikipedia

    en.wikipedia.org/wiki/Wildcard_character

    In SQL, wildcard characters can be used in LIKE expressions; the percent sign % matches zero or more characters, and underscore _ a single character. Transact-SQL also supports square brackets ([and ]) to list sets and ranges of characters to match, a leading caret ^ negates the set and matches only a character not within the list.

  4. Help:Searching/Regex - Wikipedia

    en.wikipedia.org/wiki/Help:Searching/Regex

    A regex search scans the text of each page on Wikipedia in real time, character by character, to find pages that match a specific sequence or pattern of characters. Unlike keyword searching, regex searching is by default case-sensitive, does not ignore punctuation, and operates directly on the page source (MediaWiki markup) rather than on the ...

  5. UTF-8 - Wikipedia

    en.wikipedia.org/wiki/UTF-8

    It was designed for backward compatibility with ASCII: the first 128 characters of Unicode, which correspond one-to-one with ASCII, are encoded using a single byte with the same binary value as ASCII, so that a UTF-8-encoded file using only those characters is identical to an ASCII file.

  6. Basic access authentication - Wikipedia

    en.wikipedia.org/wiki/Basic_access_authentication

    The resulting string is encoded into an octet sequence. The character set to use for this encoding is by default unspecified, as long as it is compatible with US-ASCII, but the server may suggest the use of UTF-8 by sending the charset parameter. [9] The resulting string is encoded using a variant of Base64 (+/ and with padding).

  7. Comparison of regular expression engines - Wikipedia

    en.wikipedia.org/wiki/Comparison_of_regular...

    Regular Expression Flavor Comparison – Detailed comparison of the most popular regular expression flavors; Regexp Syntax Summary; Online Regular Expression Testing – with support for Java, JavaScript, .Net, PHP, Python and Ruby; Implementing Regular Expressions – series of articles by Russ Cox, author of RE2; Regular Expression Engines

  8. Perl Compatible Regular Expressions - Wikipedia

    en.wikipedia.org/wiki/Perl_Compatible_Regular...

    Perl Compatible Regular Expressions (PCRE) is a library written in C, which implements a regular expression engine, inspired by the capabilities of the Perl programming language. Philip Hazel started writing PCRE in summer 1997. [ 3 ]

  9. SQL syntax - Wikipedia

    en.wikipedia.org/wiki/SQL_syntax

    Title Authors ----- ----- SQL Examples and Guide 4 The Joy of SQL 1 An Introduction to SQL 2 Pitfalls of SQL 1 Under the precondition that isbn is the only common column name of the two tables and that a column named title only exists in the Book table, one could re-write the query above in the following form: